Stinky Holding Tank

Make sure that the roof vent is not obstructed. I've had wasps make a nest in the roof termination cap that created odors when the toilet is flushed. I also use Venturi type roof vent caps to help draw odors from the holding tanks.

I make sure that the roof vent is closed when I flush. When done flushing, I open the roof vent and then turn on the fan for a few seconds.

Use holding tank chems. - this is what they are for.

Fact is the toilet is in most cases directly over the holding tank and when you flush you WILL get an odor. The best way to prevent it is to use plenty of water per flush, and only hold the valve open as long as it takes to get rid of the “stuff”. Make sure there isn’t a vent on the bathroom open when you flush as it will help draw fumes into to bathroom.

First, get a toilet tank wand that attaches to the end of a garden hose. Second drain your black tank. Third, stick the wand down the toilet. Fourth, turn the water on to the wand. Fifth, rinse the tank and spray that water all around for a while.

(It really helps if you have a clear section of pipe on your trailer tank outlets so you can see what's actually coming out. But I think you'll be shocked at how much "stuff" will come out if you flush the tank this way).

Sixth, after the water runs clear from the tank, close of your valves, pour a cup of bleach and a few good squirts of Dawn dishwashing liquid down the toilet and use the wand again running water, to stir things up really good. Seventh, After running the wand a few minutes, after the bleach and Dawn bubble up real good, dump that out and use your tank as normal. Smells will be gone.

Don't matter how much or how often you dump, or how much or how little water there is when you do, when you push the pedal and you have a wiff of bad smell, there's "****" down there that needs to be cleaned out. It's just that simple.

use happy camper additive. it gets rid of the smell not give it a perfume treatment like the other stuff on the market

Not sure how well this stuff would work on an RV that just stays in one place as it seems to me that cleaning action takes place as the liquids slosh around, but I am very satisfied with Happy Campers;

http://www.1-happycamper.com/

In any case, I can't see how your tank can get clean if a significant portion of the inside is not in contact with water. You might try to fill the tank to the top after adding the cleaner and letting it set for a while. I still don't think you'll get the results if you don't agitate the liquid though. But filling with water for a soak has got to at least help.

We use Thetford Aqua-Kem Toilet Chemicals with enzymes and a deodorizer. Our RV is stored for several months and there's no unpleasant smell. Follow the directions.

you might get better response if this was in the right forum.
bumpy

Your not flushing the tank enough all it is.Also makesure the pipe from tpilet to tank gets cleaned.If a older toilet **** could be built up inside it needs more cleaning